{"id":"GHSA-cq4q-cv5g-r8q5","summary":"Netty: QUIC stateless reset token material exposed through header-visible connection IDs","details":"### Summary\nNetty QUIC exposes the stateless reset token on the network path when using the default HMAC-based connection-ID and stateless-reset-token generators. The reset token for the server's current source connection ID can be derived from bytes that appear as the connection ID in QUIC headers after a source-CID rotation. An on-path attacker observing the headers can use the token to perform a Denial of Service by sending a spoofed Stateless Reset packet.\n\n### Details\nThe sign-based connection ID generator (HmacSignQuicConnectionIdGenerator) and reset token generator (HmacSignQuicResetTokenGenerator) both evaluate HMAC-SHA256 with the same JVM-wide static key (io.netty.handler.codec.quic.Hmac).\n\nDuring source CID rotation (QuicheQuicChannel.newSourceConnectionIds), the current server source CID C is used as input to produce the next CID N. The stateless reset token for C is defined over HMAC(K, C), specifically the first 16 bytes. The next CID N is the first L bytes of the same digest, where L = |C|.\n\nWhenever L ≥ 16, the first 16 bytes of N are exactly the stateless reset token for C. Because N is carried in QUIC headers as a connection ID, an observer can read the headers and learn the reset token without decrypting the payload.\n\nThis directly violates RFC 9000\nhttps://datatracker.ietf.org/doc/html/rfc9000#name-calculating-a-stateless-res: `The stateless reset token MUST be difficult to guess.`\nAdditionally https://datatracker.ietf.org/doc/html/rfc9000#name-stateless-reset-oracle\n\n### Impact\nInformation Disclosure and Denial of Service. An on-path attacker can obtain the stateless reset token from the connection ID header and attempt to abruptly close the client side of the connection by sending a spoofed Stateless Reset datagram.","aliases":["CVE-2026-50009"],"modified":"2026-09-10T03:51:08.617672687Z","published":"2026-06-15T20:44:20Z","database_specific":{"cwe_ids":["CWE-200","CWE-330"],"severity":"MODERATE","github_reviewed":true,"github_reviewed_at":"2026-06-15T20:44:20Z","nvd_published_at":"2026-06-12T16:16:31Z"},"references":[{"type":"WEB","url":"https://github.com/netty/netty/security/advisories/GHSA-cq4q-cv5g-r8q5"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-50009"},{"type":"PACKAGE","url":"https://github.com/netty/netty"},{"type":"WEB","url":"https://github.com/netty/netty/releases/tag/netty-4.2.15.Final"}],"affected":[{"package":{"name":"io.netty:netty-codec-classes-quic","ecosystem":"Maven","purl":"pkg:maven/io.netty/netty-codec-classes-quic"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"4.2.0.Final"},{"fixed":"4.2.15.Final"}]}],"versions":["4.2.1.Final","4.2.10.Final","4.2.11.Final","4.2.12.Final","4.2.13.Final","4.2.14.Final","4.2.2.Final","4.2.3.Final","4.2.4.Final","4.2.5.Final","4.2.6.Final","4.2.7.Final","4.2.8.Final","4.2.9.Final"],"database_specific":{"last_known_affected_version_range":"\u003c= 4.2.14.Final","source":"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/06/GHSA-cq4q-cv5g-r8q5/GHSA-cq4q-cv5g-r8q5.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:L"}]}